I. Field
The following description relates generally to wireless communications, and more particularly to implementing antenna virtualization in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various types of communication; for instance, voice and/or data can be provided via such wireless communication systems. A typical wireless communication system, or network, can provide multiple users access to one or more shared resources (e.g., bandwidth, transmit power, . . . ). For instance, a system can use a variety of multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM), Orthogonal Frequency Division Multiplexing (OFDM), and others.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple user equipments (UEs). Each UE can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to UEs, and the reverse link (or uplink) refers to the communication link from UEs to base stations. This communication link can be established via a single-in-single-out, a multiple-in-single-out or a multiple-in-multiple-out (MIMO) system.
MIMO systems commonly employ multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NT transmit and NR receive antennas can be decomposed into NS independent channels, which can be referred to as spatial channels, where NS≦{NT, NR}. Each of the NS independent channels corresponds to a dimension. Moreover, MIMO systems can provide improved performance (e.g., increased spectral efficiency, higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.
MIMO systems can support various duplexing techniques to divide forward and reverse link communications over a common physical medium. For instance, frequency division duplex (FDD) systems can utilize disparate frequency regions for forward and reverse link communications. Further, in time division duplex (TDD) systems, forward and reverse link communications can employ a common frequency region so that the reciprocity principle allows estimation of the forward link channel from the reverse link channel.
Wireless communication systems oftentimes employ one or more base stations that provide a coverage area. A typical base station can transmit multiple data streams for broadcast, multicast and/or unicast services, wherein a data stream may be a stream of data that can be of independent reception interest to a UE. A UE within the coverage area of such base station can be employed to receive one, more than one, or all the data streams carried by the composite stream. Likewise, a UE can transmit data to the base station or another UE.
A wireless communication apparatus (e.g., UE, base station, . . . ) can be equipped with a plurality of physical transmit antennas. Oftentimes, respective signals are provided to utilize the plurality of physical transmit antennas. Thus, for instance, four signals can be provided to employ four physical transmit antennas (e.g., each physical transmit antenna sends a respective one of the four signals, . . . ). However, significant overhead can result from the foregoing. Moreover, employment of a subset of the plurality of physical transmit antennas can result in inefficient utilization of the physical transmit antennas, power amplifiers (PAs) associated with the physical transmit antennas, and so forth. According to another illustration, a receiving wireless communication apparatus (e.g., UE, base station, . . . ) can be unable to receive and/or process the plurality of signals sent by the plurality of physical transmit antennas. Following this illustration, the number of physical transmit antennas with which the wireless communication apparatus is equipped can exceed a number of physical transmit antennas supported by the receiving wireless communication apparatus.